Configuring AIS in EVPN Networking

Configuring AIS prohibits a MEP in an MD of a higher level from sending the same alarm as that sent by a MEP in an MD of a lower level to the NMS.

Context

As shown in Figure 1, the MEPs configured on the access interfaces of CE1 and CE2 reside in level-6 MD1. The MEPs configured on PE1 and PE2 reside in level-3 MD2. When a fault occurs, a MEP in level-3 MD2 first detects the fault and sends an alarm to the NMS. After a certain period, a MEP in level-6 MD1 also detects the fault and sends the same alarm to the NMS. Therefore, the AIS function needs to be configured on the PEs to prohibit the MEP in the MD of a higher level from sending alarms to the NMS.

Figure 1 Networking diagram of configuring AIS in EVPN networking

Procedure

Perform the following steps on a PE:
1. Run system-view
  
  The system view is displayed.
2. Run cfm md md-name
  
  The MD view is displayed.
3. Run ma ma-name
  
  The MA view is displayed.
4. Run map evpn vpn-instance evpn-instance-name
  
  Associates the MA with a EVPN instance.
5. Run ais enable
  
  AIS is enabled for the current MA.
6. (Optional) Run ais link-status interface { interface-name | interface-type interface-number }
  
  AIS is configured to monitor interfaces in the current MA.
7. (Optional) Run ais interval interval-value
  
  The interval at which AIS packets are sent is set.
  
  If the range of VLANs to which AIS packets are to be sent is set, setting the interval at which AIS packets are sent to 60s is recommended.
8. Run ais level level-value
  
  The level of AIS packets to be sent is set.
9. Run ais vlan { pe-vid pe-vid ce-vid { low-ce-vid [ to hig-ce-vid ] } &<1-10> | vid { low-vid [ to high-vid ] } &<1-10>} mep mep-id
  
  The range of VLANs to which AIS packets are to be sent is set.
10. Run commit
  
  The configuration is committed.
Perform the following steps on a CE:
1. Run system-view
  
  The system view is displayed.
2. Run cfm md md-name
  
  The MD view is displayed.
3. Run ma ma-name
  
  The MA view is displayed.
4. Run map vlan vlan-id
  
  The MA is bound to the current VLAN.
5. Run ais enable
  
  AIS is enabled for the current MA.
6. (Optional) Run ais suppress-alarm
  
  Alarm suppression is enabled for the current MA.
  
  In an MD nesting scenario, if alarm suppression is enabled for the MD of a high level, a MEP in this MD does not send alarms that a MEP in an MD of a low level has sent to the NMS after receiving an AIS packet.
7. Run mep mep-id mep-id alarm ais disable
  
  Disables the alarm reporting function of a specific alarm indication signal (AIS).
8. Run commit
  
  The configuration is committed.

Checking the Configurations

After completing the configurations, run the display cfm ma command on a PE to check information about MAs.

The command output shows that the Sending Ais Packet field is displayed as Yes.
Run the display cfm ma command on a CE to check information about MAs.

The command output shows that the Suppressing Alarms field is displayed as Yes.